Well,I know the game is several years old but I decided to start it for the first time today.I am using an Acekard with the latest AKAIO and the latest usercheat.dat.
My little story is this.I started the game normally,created a Character and finished the first Guild Quest.The game saved normally and after that I finished my game session.
The next time I played,I decided to use some cheats for a quick level up.I enabled the anti-piracy code and some exp multipliers and started again.And then,I discovered that my save was lost.
I disabled cheats and started again.My save file was perfectly untouched.When I re-enabled cheats,my save had dissapeared.After that,I tried every possible combination in the settings but nothing worked.
What can I do?Has anyone else found a solution for this problem?

Or stick to offline if you wanna cheat. But if it's not working... heh, then don't cheat. Really, it's not that difficult to level up, unless you wanna max level, in which case you'll have to invest considerable time to do that.

what do you mean that your save is lost? the .sav file is physically missing from the micro sd card or do you mean that your save file is corrupted and not loading? did you happen to tick on the option to save files as .nds.sav instead of .sav? if the save file is still on the card, have you tried using that save file with a ds emulator? can you please verify by crc value that the rom on your card is a clean dump?

you may have corrupted the rom/save file by using cheats. i could be the cheat engine, cheats for that game weren't well tested, or that your microsd card just needs a reformat.

after you verify whats working, whats missing, what isn't corrupted, then try a fresh format of the msd card. this time turn off all patching except for cheats (ds-download play, soft-reset, etc). this way only cheats will be in RAM and the chances of overwriting something important will be less.